FDA Issues Emergency Use Authorization for Ivomec to Prevent Screwworm in Cattle

FDA CVM Veterinary Medicine Updates

Published February 5th, 2026

Detected March 12th, 2026

Summary

The FDA has issued an Emergency Use Authorization (EUA) for Ivomec (ivermectin) injectable solution to prevent New World screwworm infestations in cattle. This authorization allows for over-the-counter use under specific conditions and is effective until the declared emergency is terminated.

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What changed

The U.S. Food and Drug Administration (FDA) has issued an Emergency Use Authorization (EUA) for Ivomec (ivermectin) injectable solution, allowing its use to prevent New World screwworm (NWS) infestations in cattle. The EUA is based on the determination that Ivomec may be effective for prevention when administered under specific conditions, and its benefits outweigh its risks. The product is not for use in female dairy cattle producing milk for human consumption or calves processed for veal, and has a 35-day slaughter withdrawal period. This authorization is in effect until the emergency declaration for NWS is terminated.

Producers are responsible for using Ivomec according to the product labeling and fact sheet. The FDA encourages responsible use to mitigate antiparasitic resistance. While Ivomec is available over-the-counter, producers should use it only when medically necessary as part of a comprehensive parasite management strategy. This action marks a significant expansion of Ivomec's approved uses, previously limited to treating other parasites in various livestock.

What to do next

Review FDA's Emergency Use Authorization for Ivomec and associated labeling and fact sheets.
Ensure Ivomec is administered to cattle only under the conditions specified in the EUA and product labeling.
Adhere to the 35-day slaughter withdrawal period for cattle treated with Ivomec.

Source document (simplified)

February 5, 2026

Today the U.S. Food and Drug Administration issued an Emergency Use Authorization (EUA) for Ivomec (ivermectin) injectable solution against New World screwworm (NWS). The agency has concluded that based on the scientific evidence available, it is reasonable to believe that Ivomec may be effective for the prevention of infestations caused by NWS larvae (myiasis) in cattle when administered within 24 hours of birth, at the time of castration, or when a wound appears, and the known and potential benefits of the product outweigh its known and potential risks.

Ivomec is not for use in female dairy cattle producing milk for human consumption and calves that will be processed for veal. The slaughter withdrawal period for cattle is 35 days.

This EUA will be effective until it is revoked or the HHS Secretary terminates the declaration that the potential public health emergency presented by NWS justifies the emergency use authorization of animal drugs for NWS.

Ivomec is available over the counter without a prescription. Producers are responsible for using Ivomec in accordance with the product labeling and fact sheet. To reduce the risk of antiparasitic resistance and preserve drug effectiveness against both NWS and other parasites, producers are encouraged to use antiparasitic drugs like Ivomec only when medically necessary and as part of a comprehensive parasite management strategy.

The FDA has previously approved Ivomec to treat and control other parasites in cattle, swine, reindeer and American bison.

Ivomec is sponsored by Boehringer Ingelheim Animal Health USA, Inc. based in Duluth, Georgia.